The present invention relates to fans for ventilation and specifically to centrifugal fan assemblies.
Centrifugal fan assemblies are commonly used to ventilate spaces, such as buildings or large equipment. Such assemblies, often called ventilators, typically include a housing, a drive system (typically including an electric motor) supported by the housing, and a fan rotor driven by the drive system. It is known to have a fan rotor with two sets of vanes, one for moving air out of the building or space, commonly called blades, and another for moving air over the drive system for cooling.